Concrete form and joint forming member therefor



Feb. 24, 1970 w. F. WELCH 3,497,172

CONCRETE FORM AND JOINT FORMING MEMBER THEREFOR Filed April 5, 1967 f?. WR 1.?. f5.2.

2 Sheets-Sheet l INVENTOR WARREN E WELCH BMM@ ATTORNEYS CONCRETE FORM AND JOINT FORMING MEMBER THEREFOR Filed April 5, 1967 W. F. WELCH Feb. 24, 1970 2 Sheets-Sheet 2 INVENTOR WARREN E WELCH ATTORNEYS United States atent 3,497,172 CONCRETE FORM AND JOINT FORMING MEMBER THEREFOR Warren F. Welch, Parsons, Kans., assignor, by mesne assignments, to Superior Concrete Accessories, Inc., Franklin Park, Ill., a corporation of Delaware Filed Apr. 5, 1967, Ser. No. 628,598 Int. Cl. E01c 11/04 U.S. Cl. 249-3 18 Claims ABSTRACT F THE DISCLOSURE This disclosure relates to a concrete form of the type used in forming a key contracting joint between adjacent concrete slabs and a joint forming member therefor. The joint forming member is characterized in that it utilizes a plurality of longitudinally spaced means for engaging a support means, each of said engaging means including a strap means and/ or a plurality of inverted ledge means. The concrete form comprises a plurality of aligned stakes and a joint forming member as aforedescribed wherein said joint forming member is supported upon said stakes through the use of said strap means and/or said inverted ledge means. The joint forming member preferably includes a folded-over portion extending downwardly from the upper edge thereof.

BACKGROUND OF THE INVENTION Heretofore, many concrete formes of the type used in forming the key contraction joint between adjacent concrete slabs have been proposed, especially for monolithically poured concrete slabs, e.g. see U.S. Patent Nos. 3,143,783 (Class 25-118), 3,057,269 (Class 94-17), and Re. 24,921 (Class 94-17). Many of these forms have had useful application. However, each of these forms have suffered from a number of disadvantages. For example, many of the prior art forms were disadvantageous in that a considerable amount of expense and time was required to install same. Additionally, other prior art forms were disadvantageous due to the fact that they could not be used in concrete slabs subjected to relatively large loads without spalling occurring. Further, many of the prior art concrete forms were disadvantageous since none of same contained an inexpensive means for preventing a joint forming member used within a concrete form from floating upwardly within the mass of concrete following pouring thereof. It has been discovered, however, that each of the foregoing disadvantages may be quickly and easily overcome through the use of a new and novel concrete form and a unique joint forming member therefor, said concrete form comprising a plurality of aligned stakes and said joint forming including a plurality of longitudinally spaced means for engaging said stakes, each of said means including a strap means and/ or a plurality of longitudinally spaced inverted ledge means, said strap means and/or said inverted ledge means serving to secure said joint forming member to said plurality of aligned stakes in a predetermined supporting manner.

Accordingly, one of the principal objects of this invention is to provide a new and improved concrete form of the type used in forming a key contraction joint between adjacent concrete slabs.

Another object of this invention is to provide a concrete form which may be used with concrete slabs which are to be subjected to relatively heavy loads.

3,497,172 Patented Feb. 24, 1970 ICC Another object of this invention is to provide a concrete form which may be easily and quickly installed and which at the same time incorporates inexpensive means for preventing the joint forming member used therein from floating upwardly under the influence of the pressure existing within the concrete following the pouring thereof.

Another object of this invention is to provide a new and novel joint forming member for forming a key contraction joint between the adjacent concrete slabs.

Another object of this invention is to provide an improved concrete form of the type used in forming a key contraction joint between adjacent slabs which eliminate the use of an inverted stake pocket disposed adjacent the upper portion of the joint forming member used in such form and disposed in a direction opposite to the key deformation porion of such member.

Another object of this invention is to provide a concrete slab forming member which is inexpensive to manufacture and which may be employed in the construction of parking areas and floors which may be quickly and easily installed.

Another object of this invention is to provide a joint member for forming a key contraction joint between adjacent concrete slabs, said member being characterized in the use of a plurality of longitudinally spaced means formed within the upper portion thereof for engaging a support means to support said member with the upper edge of said member being disposed along a predetermined grade level, each of said engaging means comprising a strap means, each of said strap means being disposed be- .low said upper edge, each of said strap means being integrally connected at each end thereof to a part of said member, and each of said strap means thereof to a part of said member, and each of said strap means having a portion thereof extending outwardy from the adjacent surface of said member.

Another object of this invention is to provide a joint forming member including a plurality of longitudinally spaced means for engaging a support means used to support said member, said engaging means comprising a plurality of longitudinally spaced strap means and a plurality of longitudinally spaced inverted ledge means.

Another object of this invention is to provide a joint forming member having a folded-over portion extending downwardly from the upper edge thereof.

Another object of this invention is to provide a joint forming member including a generally U-shaped portion integrally connected at each end thereof to said member.

Another object of this invention is to provide a joint forming member utilizing a plurality of longitudinally spaced strap means each of which is, in cross-section, generally C-shaped in configuration and a plurality of longitudinally spaced inverted ledge means each of which includes a pair of boss portiops.

Another object of this invention is to provide a concrete form used in forming a key contraction joint between adjacent concrete slabs, said joint comprising a plurality of aligned stakes and a joint forming member as aforedescribed.

Another object of this invention is to provide a concrete form as aforedescribed in which each of said stakes has a recess portion formed therein, said recess portion cooperating with said strap means to prevent vertical movement of the joint forming member relative to said stakes.

3 SUMMARY oF THE INVENTION The present invention substantially overcomes or alleviates the problems mentioned above and has various other advantages which result in a greatly improved concrete form. Generally stated, a yjoint forming member constructed in accordance with the subject invention comprises upper and lower longitudinally extending, generally co-planar portions and a longitudinally extending key deformation portion interposed between and connected to said upper and lower portion. The upper planar portion is formed with an upper edge. The joint forming member includes a plurality of longitudinally spaced means formed within the upper planar portion for engaging a support means to support said member with the upper edge of said planar portion being disposed along a predetermined grade level. Each of said engaging means comprises a strap means. Each of said strap means is disposed below said upper edge, is integrally connected at each end thereof to a part of said upper portion, and has a portion thereof extending outwardly from the adjacent surface of said upper planar portion. Each of said engaging means also preferably includes an inverted ledge means formed above said strap means but below said upper edge. Each of said strap means is preferably formed, in cross-section, in a generally C-shaped configuration wherein the convex portion of such configuration is disposed intermediate the concave portion of such configuration and the adjacent part of said upper planar portion. Each of said inverted ledge means preferably includes a pair of boss portions. Said member also preferably includes a folded-over portion extending downwardly against at least a part of said upper planar portion.

In application, a plurality of support means or aligned stakes are driven into the sub-base upon which the concrete slab is to be supported. A joint forming member as aforedescribed is then mounted upon said stakes withv the strap means being disposed in partial encompassing engagement about a corresponding one of each of said stakes and with the inverted ledge means being disposed in abutting engagement against the upper end f a corresponding one of said stakes. Each of the stakes preferably includes a recess means formed adjacent the upper end thereof. Said recess means and said convex portion of said strap means cooperate to prevent vertical movement of the member relative to said stakes.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing objects and other advantages of the invention will become apparent from the following description and claims and the accompanying drawings, wherein:

FIGURE 1 is a vertical section through adjoining concrete sla'bs of a concrete slab showing one embodiment of a concrete form constructed in accordance with the subject invention.

FIGURE 2 is a perspective view of the concrete form shown in FIGURE 1;

FIGURE 3 is a cross-sectional view taken along line 3-3 of FIGURE 2;

FIGURE 4 is a cross-sectional view taken along` line 4-4 of FIGURE 2;

FIGURE 5 is a side elevation of one embodiment of a stake useful in a concrete form constructed in accordance with the subject invention;

FIGURE 6 is an end elevational view of the stake shown in FIGURE 5;

FIGURE 7 is a plan view of the stake shown in FIG- URE 5;

FIGURE 8 is a side elevational view of another embodiment of a stake useful in a concrete form constructed in accordance with the subject invention;

FIGURE 9 is an end elevational view of the stake shown in FIGURE 8; and

FIGUR-E l0 is a cross-sectional view of the upper portion o f a, concrete form constructed in accordance with the subject invention utilizing the stake shown in FIGURES s and 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, in FIGURE l is shown a vertical section through adjoining concrete slabs of a concrete oor or the like showing the preferred embodiment of a concrete form 20 constructed in accordance with the subject invention. The concrete form 20 is of the type used in forming a key contraction joint between adjacent concrete slabs 22 and 24 and comprises a plurality of support means or aligned stakes 26 (only one of which is shown) and an elongated relatively rigid sheet material member 28, see also FIGURE 2. Each of the stakes 26, see FIGURES 5-7, has a generally vertically disposed body portion 30, a boss portion 32, and a plurality of apertures 33. The upper ends 34 of each of the stakes 26 are disposed along a predetermined grade level represented in FIGURE l by dotted line 36.

The member 28 comprises upper and lower longitudinally extending, generally cof-planar portions 38 and 40 and a longitudinally extending key deformation portion 42 interposed between and connected to said upper and lower planar portions 38 and 40, said planar portions 38 and 40 being disposed against vertically disposed surface portions of said stakes 216. In FIGURE 2, it will be noted that the corners 44 and 46 of the key deformation portion 42 are arcuately shaped. The purpose for this is to minimize any undue stress concentrations forming within the edges of the concrete formed adjacent said corners 44 and 46. The upper and lower planar portions 38 and 40 incorporate longitudinally extending corrugations 48 which increase the overall rigidity of member 38. The upper planar portion 38 of member 28 has a folded-over portion S0 which also functions to increase the rigidity of member 28. The upper planar portion 38 is disposed at a predetermined grade level such as that represented by the upper surface of the concrete slabs 22 and 24 as indicated by line 52 in 'FIGURE 1. Member 28 may also include a plurality of apertures 54 (only one of 4which is shown in FIGURE 2) longitudinally spaced along the lower planar portion 40 of member 28. The upper planar portion 38 of member 28 has an upper edge 56, Additionally, the upper edge portion 38 has' a plurality of longitudinally spaced means 58, see FIGURE 2, formed therein. Each' of said means 58 is constructed for engaging portions of a stake whereby the upper edge 56 is disposed along a predetermined grade level, such as the grade level indicated by line 52 in FIGURE 1. Each of said engaging means 58 includes a strap means 60 and, preferably, an inverted ledge means 62. Each inverted ledge means 62 is disposed a predetermined distance below the upper edge 516. Each strap means 60 is disposed a predetermined distance below the inverted ledge means 62. Each strap means 60 is integrally connected at the ends thereof to a part of said upper planar portion 38. Each inverted ledge means 62 is likewise integrally connected to the upper planar portion 38. As shown in FIGURES 2 and 3, each inverted ledge means 62 comprises a pair of boss portions `64. Each strap means 60 is formed, in cross-section, generally C- shaped in configurati-on. The convex portion 66 of each C-shaped configuration is disposed intermediate the concave portion 68 and the adjacent part of upper planar portion 38. The member 28 is mounted upon the stakes 26 in a manner whereby each of said stakes 26 has an upper part thereof disposed in contacting engagement with the convex portion of the strap -means 60 and with the upper end 34 thereof disposed in abutting engagement with a corresponding one of said inverted ledge means 62. Thus, the strap means 60 is disposed in partial encompassing engagement about the stake 216.

As shown in FIGURES l and 2, the concrete form 20 may also include a means 70 such as a screw disposed within one of a plurality of apertures 33 formed within stakes 26 and a corresponding aperture 54 formed in the lower planar portion 40 of member 28. The purpose of using this means or screw 72 in this manner is to insure against vertical movement of member 28 relative to the stakes 26. The key deformation portion 42 is preferably provided with a number of suitably spaced apertures 74 which are adapted to receive slidably a metal dowel or rod 76.

Although the vertical movement of the member 28 relative to the stakes 26 is greatly minimized as a result of the frictional interface existing ybetween the stakes 26 and of the corresponding strap means `60, it has been found that the tendency of the member 28 to move relative to the stakes 26 may :be resisted even further through the use of stakes similar to stake 78 as shown in FIG- URES 8-10. Stake 78 has a body portion 80, an upper end 82, and boss portions 84 and 86 which cooperate to form a recess portion 88. As shown in FIGURE 10, the recess portion 88 is formed a predetermined distance below the upper end 82 thereof, said distance representing the same distance between the inverted ledge means 62 and the approximate center of strap means 60. When the member 28 is positioned relative to the stake 78 as shown in FIGURE l0, the recess portion 88 of stake 78 cooperates with the convex portion 66 of the strap means i60 to resist and prevent movement of member 28 relative to the stakes 78.

Referring now to the drawings, the installation of the concrete form 20 as shown in FIGURE l is now described. After the sub-grade or sub-base 90 has been formed and suitable side forming (not shown) has been installed, a string or line (not shown) is extended from one side of the sub-base 90 to the other side thereof at a predetermined grade level, preferably the grade level represented by the dotted line 36. Next, a section or sections of joint forming members 28 are laid adjacent the line established yby said string. The purpose for this is to facilitate the spacing of the stakes 26 along the -line established by such string. However, it will be appreciated that the spacing may be determined in any of several other ways since the spacing between the engaging means 58 of member 28 will admit of some variation in installation thereby precluding exact, precise spacing of the stakes. For example, the horizontal length of the strap means 60 is approximately 3 times the width of the stake that is to be installed therein. Thus, where a 2-foot spacing interval is desired or required, the length of the strap means 60 is made sufficiently long to permit the center to center spacing between the engaging means 58 to vary up to approximately three or four inches. After the member or members 28, depending on the width of the concrete slabs, are positioned upon the sub-grade as described, the stakes are installed one at a time along the line established by this string at the desired spacing interval. Each stake is driven into the subgrade 90 until the upper end thereof is disposed along a predetermined grade level, preferably the grade level as represented by the dotted line 36. Next, each of the members 28 is mounted upon the stakes by positioning the member 28 until each of the upper ends of the stakes is disposed in abutting engagement with a corresponding one of said ledge means 62. After the member or members 28 have Ibeen installed upon the stakes as described, it will be readily appreciated that the upper edge 56 of the upper planar portion 38 will be disposed along a predetermined grade level such as the grade level represented by line 50, said line 50 normally coinciding with the upper surface of the concrete slabs 22 and 24. Thus, said upper edge S6 will serve and function as a screed key to facilitate the leveling of the freshly poured concrete to a predetermined grade level. If desired or required, dowels or rods 76 may be installed within the dowel apertures 74. Additionally, the means or screw 70 may be installed in one of the apertures 54 and caused to extend through a corresponding aperture 33 formed in the lower portion of each of the stakes 26. After the foregoing has been accomplished, the concrete form is ready for the pouring of concrete. The concrete is preferably poured simultaneously on both sides of the concrete form. However, where only one slab is formed at a time, it is preferred that the concrete slab which is disposed adjacent the convex portion of the member 28 be first poured. After the pouring of the concrete slabs 22 and 24, the upper surface of said slabs may be suitably leveled or smoothed by means of a rod or leveling member which may be supported, at least in part, during its back and forth movement on the upper edge 56 of member 28. Thus, the upper straight edge 56 of member 28 functions as a screed.

Referring now to FIGURE 10, the concrete form shown in FIGURE l0 is installed in a manner similar to that described above with respect to concrete form 20. As previously indicated, due to the cooperation between the recess portion 88 of stake 78 and the convex portion 66 of strap means 60, there is seldom any need to use the means or screw 70 as Shown in FIGURES l and 2 to prevent vertical movement of the member 28 relative to the stakes 78.

In vieW of the foregoing, it is to be understood that member 28 may be formed without the use of inverted ledge means 62 as shown in FIGURES l-4. Under this circumstance, it is highly desirable to use such a member in combination with either stakes 26 having apertures 33 formed therein or stakes 78 which may be formed with or without apertures similar to aperture 33. However, as previously indicated, it is preferred that the joint forming member include the inverted ledge means 62 as shown in FIGURES 1-4.

As shown in FIGURE 2, each member 28 has a U shaped portion 92 formed inthe upper planar portion adjacent each end thereof. An elongated member 94 such as a nail is disposed within adjacent U-shaped portions `92 to provide, in combination therewith, a means for rigidizing the abutting ends of members 28.

With respect to the folded-over portion S0 it will be noted that said portion 50 extends downwardly a predetermined distance from the upper edge 56. Preferably, the folded-over portion 50 terminates at a distance above the inverted ledge means 62 and preferably above the arcuately shaped boss portions 64.

From the foregoing, it will be readily obvious that a new and novel concrete form and unique joint forming member therefor has been described. Further, several advantages are obtained from using the concrete form and joint forming member therefor described herein which were not obtainable in prior art concrete forms and joint forming members therefor. For example, a joint forming member constructed in accordance with the subject invention may be formed from a reduced amount of material as compared with the prior art devices. Additionally, a concrete form constructed in accordance with the subject invention may be easily, quickly and accurately installed by a single workman in the field. Further, concrete forms constructed in accordance with the subject invention may -be used for relatively thick concrete slabs, i.e., 8 inches or more, without experiencing detrimental spalling or breaking thereof adjacent the upper surfaces of the concrete form. Additionally, concrete forms constructed in accordance with the subject invention provide an inexpensive means for securing the joint forming member thereof against vertical movement relative to the supporting stakes thereby insuring that the upper edge of such member is properly positioned to function as a screed. Also, concrete forms constructed in accordance 'with the subject invention may be used in conjunction with concrete slabs which are subjected to relatively heavy wheel loads and beneficial results may be obtained for both relatively thick concrete slabs and relatively thin concrete slabs. Further, a concrete form constructed in accordance with the subject invention is not subjected to being inadvertently blown or knocked off the supporting stakes, and this is so even though the screw means 70 is omitted therefrom.

It is to be understood that this invention is not limited to the exact embodiments of the concrete forms and joint forming members shown, which are merely by way of illustration and not limitation, as various other forms and modifications will be apparent to those skilled in the art, and it is therefore intended that the appended claims cover all such changes and modifications.

I claim:

1. A concrete form of the type used in forming a key contraction joint between adjacent concrete slabs, said joint comprising: a plurality of aligned stakes; and an elongated relatively rigid sheet material member, said member including upper and lower longitudinally extending, generally co-planar portions and a longitudinally extending key deformation portion interposed between and connected to said upper and lower planar portions, said upper planar portion having an upper edge, said member including a plurality of longitudinally spaced means formed within the upper planar portion for engaging portion of said stakes whereby the upper edge of said planar portion is dispos-ed along a pre-determined grade level, each of said engaging means comprising a strap means and an inverted ledge means, said inverted ledge means being disposed a predetermined distance below said upper edge, said strap means `being disposed below said inverte-d ledge means, said strap means being integrally connected at the ends thereof to a part of said upper planar portion and said inverted ledge means being integrally connected to said upper planar portion; each of said stakes having an upper part disposed in abutting engagement with a corresponding one of said inverte-d ledge means, and each of said stakes being positioned whereby a corresponding one of said strap means is disposed in partial encompassing engagement thereabout.

2. A concrete form of the type as described in claim 1 in which said upper planar portion includes a folded-over portion extending downwardly against at least a part of said upper planar portion.

3. A concrete form of the type as described in claim 2 in which said folded-over portion terminates above said inverted ledge means.

4. A concrete form of the type as described in claim 1 in which said member also includes a pair of generally U-shaped portions integrally connected at each end thereof to said upper planar portion adjacent the ends of said upper planar portion.

5. A concrete form of the type as described in claim 1 in which each of said strap means is, in cross-section, generally C-shaped in configuration, said C-shaped configuration including a convex portion and a concave portion, said convex portion being disposed intermediate said concave portion and the adjacent part of said upper planar portion.

6. A concrete form of the type as described in claim 5 in which each of said stakes has a recess portion formed therein, said recess and said convex portion of a corresponding strap means cooperating to prevent movement of said member relative to said stakes.

7. A concrete form of the type as decribed in claim 1 in which said inverted ledge means includes a pair of boss portions.

8. A concrete form of the type as described in claim 1 in which said inverted ledge means includes a pair of arcuately shaped boss portions.

9. A concrete form of the type as described in claim 1 in which the longitudinal axes of a portion of each of said strap means are disposed generally parallel with the upper edge of said upper planar portion and also generally parallel with a line passing through each of said inverted ledge means.

10. A concrete. form of the type used in forming a key contraction joint between adjacent concrete slabs, said joint comprising: a plurality of aligned stakes; and an elongated relatively rigid sheet material member, said member including upper and lower longitudinally extending, generally co-planar portions and a longitudinally extending key deformation portion interposed between and connected to said upper and lower portions, said upper planar portion having an upper edge, said member including a plurality of longitudinally spaced means formed within the upper planar portion7 each of said means comprising a strap means, each of said strap means being integrally connected at each end thereof to a part of said upper planar portion, each strap means being, in cross section, generally C-shaped in configuration, said C-shaped configuration including a convex portion and a concave portion, said convex portion being disposed intermediate said concave portion and the adjacent part of said upper planar portion, each of said stakes including means formed thereon disposed in interlocking engagement with said strap means, said means formed on said stakes cooperating with said strap means to position said member vertically with respect to said stakes, each of said stakes being positioned with respect to a corresponding one of said strap means whereby said strap means is disposed in partial encompassing engagement with respect thereto.

11. A concrete form of the type as described in claim 10 in which the means formed on said stakes comprises a recess portion formed on one of the surfaces of said stakes.

12. A joint forming member for forming a key contraction joint between adjacent concrete slabs, said member comprising upper and lower longitudinally extending, generally co-planar portions and a longitudinally extending key deformation portion interposed between and connected to said upper and lower planar portions, said upper planar portion having an upper edge, said member including a plurality of longitudinally spaced means forming within the upper planar portion for engaging a support means to support said member with said upper edge of said upper planar portion being disposed along a predetermined grade level, each of said engaging means comprising a strap means and an inverted ledge means, said inverted ledge means being disposed a predetermined distance below said upper edge, said strap means being disposed below said inverted ledge means, said strap means being integrally connected at the ends thereof to a part of said upper planar portion and said inverted ledge means being integrally connected to said upper planar portion, each of said strap means having a portion thereof extending outwardly from the adjacent surface of said upper planar portion. y

13. A concrete form of the type as described in claim 12 in which said upper planar portion includes a folded-over portion extending downwardly against at least a part of said upper planar portion.

14. A joint forming member as described in claim 13 in which said folded-over portion terminates above said inverted ledge means.

15. A co-ncrete form of the type as described in claim 12 in which said member also includes a generallyU-shaped portion integrally connected at each end thereof to said upper planar portion adjacent each end of said upper planar portion.

16. A joint forming member as described in claim 12 in which each of said strap means is, in cross-section, generally C-shaped in configuration including a convex portion and a concave portion, said convex portion being disposed intermediate said concave portion and the adjacent surface of said upper planar portion.

17. A joint forming member as described in claim 12 in which said inverted ledge means includes a pair of boss portions.

18. A joint forming member as described in claim 12 in which the longitudinal axes of a portion of each of said strap means are disposed generally parallel with the upper 9 10 edge of said member and also generally parallel with a 3,288,042 11/ 1966 Gaetke 249-3 X line passing through each of said inverted ledge means. 3,378,968 4/1968 Shoemaker 249-3 X References Cited I. SPENCER OVERHOLSER, Primary Examiner 5 W. Assistant EXaIIllI'lEI 1,815,373 7/1931 Friberg 94--17 U.S. Cl. X.R.

1,833,509 ll/1931 Wolf 249-5 25-118; 94-17 

